Airway traffic indicator



Jan. 24, 1950 E. w. SPRINGER 2,495,296

AIRWAY TRAFFIC INDICATOR Filed Nov. 5, 1947 2 She ets-Sheet 1 FIG. I

5:3- T; 52 nun'ugg coma mans GEAR Box m SELECTOR uomn 5s 3 33 g COLORSELECTOR MASK a4 W H E-w mums S E a? le l9 37 9 5| LIGHT v w! rigmnnwwal4a SOURCE W LENS I so 26 2o a 25 a I meurmcmon k 5 610R a1 masons F655%,? SELECTOR MOTOR 45 GEAR sox ll m "'5' 5UP buncn ir i c mmswcem'vnewme scnesu g SCALE 250 X250 MILES INVENTOR. E ARL W. SPRINGER ATT' YJan. 24, 1950 E. w. SPRINGER I AIRWAY TRAFFIC INDICATOR Filed NOV. 5,l947 2 Sheets-Sheet 2 L Z:I L E cuaaem cunazn v A AMP. a A s a 2 s ma Q5:2; comm. 77 16 nggLm mun cou'mol.

FIG. 3

TRANSLUCENT I '3 W11 Ml OPTICAL PROJECTOR INVENTOR.

W. SPRINGER EARL. BY

Patented Jan. 24, 1950 UNITED STATES PATENT OFFlCE (Granted under theact oi. March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 13 Claims.

This invention relates to an airway tramc indicator and is moreparticularly described as an electro-mechanical means for plotting andshowing the positions and movement of aircraft or ships relative to abase by projecting a distinguishable image upon a screen whichrepresents the ocean surrounding a ship or a map of territory includinga base.

An important object of the invention is to provide means for projectingand moving a spot of light, representing a ship or aircraft, on atranslucent screen having drawn or printed thereon a chart or map of thearea surrounding an airport, or representing the space around a ship oran aircraft carrier.

A further object of the invention is to provide means for indicating theposition, direction of movement, height and rate of movement of anaircraftupon a screen representing a pertinent area.

Still a further object of the invention is to provide means for easilyand quickly varying the position of any light spot representing a shipor aircraft, and changing the speed, height, and direction of movementindications of the spot upon the screen.

Other objects of the invention will appear in the specification and willbe apparent from the accompanying drawings, in which,

Fig. 1 is a diagrammatical representation of an airway traflic indicatorassembly, in accordance with this invention;

Fig. 2 is a wiring diagram for the indicator assembly of Fig. 1;

Fig. 3 is a perspective of a typical projector screen as used; and

Fig. 4 is a perspective of a portion of a bank of control units for usewith a traflic indicator assembly as shown in Fig. 1.

Although it may have been proposed, heretofore, to represent thepositions, directions and other indications of flight or movements ofships upon a transparent or translucent chart, the changes in positionhave required almost constant attention and manual adjustment to be ofvalue in indicating the position and movement of a ship, or the like.The present invention provides means for accurately setting the positionand varying the speed of movement as well as the direction and otherindicated changes such as altitude, or designation of the ship may alsobe easily and quickly made with reference to a visible chart.

Referring now more particularly to Fig. 1 of the drawings, a translucentviewing screen In is represented as having an airport II (or a ship)located somewhat centrally of the screen, with a. map, chart, or milagezones ll of the area, and with radio range courses l3, or other suitableindications such as landmarks drawn or printed upon the screen to properscale.

A spot l5 of light is positioned upon the screen by reflection frommirrors l6 and I1 and from a suitable light source l8, representing anairplane (or a ship) approaching or moving away from the airport II orin some other direction. To designate aircraft identification a rotableselector mask disc having numbered transparent holes 2! with opaquenumbers or characters therein is interposed in the light path from thelight source i8, the designating number appearing upon the screen l0. Astop motor 22 is connected by a shaft 23 with the disc 20 and hasassociated switching means comprising a selector arm 24 manually movableover contacts 25 connected by separate conductors 26 to the motor andthrough a suitable battery 21 or other source of power for driving themotor.

An altitude selector and code designator may also comprise a color maskdisc 30 having openings 3| therethrough with difierent colored masks inthe openings. For example, a red mask may indicate an altitude of 500feet or below; yellow, between 500 and 1000 feet; green, above 2000 feetand so forth. This disc is rotated by a shaft 32 extending to a stopmotor 33 having connected switching means comprising a selector arm 34manually movable over contacts 35 connected by conductors 35 to themotor and through a suitable battery 31 or other sources of power fordriving the motor. The openings of this light mask are also selectivelyrotatable into the light path from the light source lenses l9 and thelight spot l5 appearing upon the screen will be colored correspondinglyto designate the altitude of the airplane to which it relates.

Each of the mirrors l6 and I1 is separately adjustable and is rotated onan axis substantially at right angles to the other by an independentwatt-hour type of motor movement at a speed in accordance with themovement of the ship to which each indicator relates, to produce acorresponding movement of the light spot IS on the screen Ill. Themirror i6 may be designated as the N-S motivator, and the mirror ll asthe E-W motivator. A shaft 40 is connected to the mirror It for turningit and this shaft is the axis of a segmental gear 4! secured theretowhich is engaged and moved to rock the mirror It accordingly by a pinion42 secured to a shaft 4! extending to a motor disc 44 through a gear boxand slip clutch 45. This disc 4 represents a motor of the wattmeter typewhich is driven by the motor coils C: and P: at right angles to eachother, receiving current, as represented in Fig. 2 from diiIerent phasesof an alternating current supply.

Similarly, the mirror I! is connected to a shaft 48 which is also theaxis of a segmental gear 49 engaging a pinion 50 on a. shaft 5|. Thisshaft 5| extends to a motor disc 52 through a gear box and slip clutch53. The disc 52 is driven by 'diflerent phase coils C1 and P1electrically connected as shown in Fig. 2.

Each of the mirrors may be independently adjusted, repositioned and setby reason of its slip clutch, and by means of a setting knob 60 or 6|connected by a flexible shaft 62 or 63 with a bevel gear 64 or 66 whichmeshes with a bevel gear 86 or 61, respectively on shaft 43 or ii.Turning either position control knob rotates the corresponding gearsegment 4| or 49 and the mirror connected therewith, without imposingundue strain upon the disc drive gear train because of the slip clutch45 or 53.

Thus the colored spot of light with a numerical designation thereon maybe set or repositioned at will and moved in accordance with the setdirection and speed of movement. Although one pair of such metermovements with the associated light source and optical system is shownin Fig. 1, any required number of such assemblies may be used asnecessitated by the traific load at the airport or other station wherethe indicators are used.

A diagrammatic arrangement of the two watthour type of meter movementsis shown in Fig. 2, with the current coils C1 and C2 for the two discmotors 44 and 52 connected in series between current amplifiers A1 andA2. Corresponding potential coils P1 and P2 for the two motors areconnected across phase one (4n) and phase two with respect to coil L1the east-west motor will run in the opposite direction but at the samespeed. For intermediate positions of the coil Lo, the east-west andnorth-south motors will be caused to rotate at proportional speeds inaccordance with the angular positions of the coil. The coil L issimilarly movable and adjustable with respect to its coils L1 and In forthe purpose of modifying the airplane speed due to the wind directionand the wind speed is changed by the resistance 19. By this means theassociated motors will be driven at such speeds as to properly representthe vector sum of the airplane and wind direction and velocity.

In using this device a number is assigned to an airplane or a flightapproaching the control area. This airplane reports by radio that it isin a position 90 miles out on the north-south range course, at anelevation of 2000 feet, and flying at a ground speed of 210 miles perhour. Upon receipt of this information, the traflic control operatorwill set up the trafllc indicator to the reported position with adetermined number desig- (2) of a source of alternating current 60 cyclepower.

An azimuth control, or phase shifter, comprises two sets of coils L1 andLe connected in quadrature in phases one and two of the source ofcurrent supply, for applying a variable potential to the motor windingcoils P1 and P2 of the watthour motors. One set of coils L1 and L2 hasan inductively related coil La mounted for relative rotatable movementby manually turning an indicator dial I0 attached thereto, the coil L3connected by conductors 1| and 12 through a variable resistance 13 withthe current amplifier A2. The other set of coils L1 and Le has aninductively related coil L4 mounted for relative rotatable movement bymanually turning an indicator dial 16 attached thereto, the coil L4connected by conductors 11 and 18 through a variable resistance 19 withthe current amplifier A1.

One variable resistance 13 may be adjusted for airplane (or ship) speed,and the other variable resistance 19 may be adjusted for wind speedcontrol as it affects the airplane.

In operation, the current amplifier outputs are connected to the coilsC1 and C: for motor discs 52 and N respectively, and when coil La isfully coupled, for example, to coil L1 the east-west ('E-W) motor (disc52) will run at maximum speed, while the north-south (N-S) motor (disc44) will remain stationary due to the quadrature relation of the inducedfields from the coils C: and P2.

If the coil 10 is reversed in position 180 degrees nation, the colorgreen, with the speed and the course as reported. At a later time, if areport comes in from this airplane or another source, and the recordedposition does not agree with the indicated position on the trafllcindicator, then by means of the position controls, Fig. 1, the indicatedposition may be corrected to agree with the most recent report. If theairplane descends to a lower altitude, say 500 feet, the altitudeselector will be shifted changing the image to the color red.

A suggested form of the control unit for the indicator is shown in Fig.4, one unit for each image projector assembly. These may be variouslygrouped for diil'erent installations and usually several units areplaced together for control by a single operator. Each unit may have acomposite directional indicator with an arm 8| positioned as the resultof the adjustment of the control arms of various control dials; shipdirection dial 10 for turning coil 1o, wind direction dial I8 forturning coil L4, ship speed dial 86 for adjusting resistance 13, andwind speed dial 88 for adjusting resistance I9. The altituderepresentation is controlled by moving an arm 90 connected with stopmotor selector arm 34 over an altitude dial 92, and the flightdesignation is controlled by an arm 94 connected with stop motorselector arm 24 and movable over a flight dial 96. The setting knob 60for the N-S mirror and SI for the E-W mirror are also commonly locatedin the control unit for easy access by the operator. If the locations ofthese units are at such a distance as to make direct or flexibleshafting connections between the controlling dials and the respectiveadjusted parts impracticable, then other remote indicating, transmittingand control means such as synchro repeaters and the like may be used.

A screen or projection map may take any of several forms; if it isdesired to plot the positions of the various images on the screen, itmay have a rough surface or a photo-surface paper may be used whichwould develop under the effect of light from the projected image. Alarge room sized screen may be used if the images are to be viewed by anumber of people. In Fig. 3 an enclosed type is shown which may bemounted on a traflic tower operating desk. It comprises a translucentscreen it which may have range courses l3 and milage zones i2, andsuitable landmarks. An optical projector system as disgrammaticallyillustrated in Fig. 1 is connected and positioned with respect to thescreen so that an enclosing casing therefor comprising a projection boxI02 is connected to the smaller end of an expanding and outwardl flaringhousing I which has the screen I. at its outer and larger end, where thescreen and the markings thereon may be viewed from the outside.

For observing and plotting the positions of ships or aircrai t relativeto a particular ship, such as an aircraft carrier, this trafllcindicator may be used aboard ship by using motor drives and opticalsystems and representing on the screen the ocean or area surrounding thehome ship. The watt-hour meter motors for this drive will have the speedcontrolled by the ship speed and the azimuth controlled by the shipsgyro compass.

With this system and apparatus the indicator may be accurately set fordirection and speed and quickly adjusted for any change or variation.Information may be derived from the approaching (or departing) air shipsand from known conditions to make any necessary changes. Each ship orflight may be distinguished and its elevation may be changed upon thesame spot which shows its path and movement over the screen withoutafiecting any other indications.

While a preferred construction and method of operation has been,described in some detail, it should be regarded as an illustration orexample rather than a restriction or limitation oftheinvention, asvarious changes may be made in the construction, combination andarrangement of the parts without departing from the spirit and scope ofthe invention.

The invention described herein ma be manufactured and used by or for theGovernment of the United States of America for government purposeswithout the payment of any royalties thereon or therefor.

I claim:

1. In a. t-rafilc indicator, 9. screen, means for projecting a light rayupon the screen, a plurality of discs each intercepting the light ray atone edge, the discs being opaque but having transparent openings whichmay be aligned with the light ray, opaque designations in the openingswhich appear in the light projected upon the screen, and stop motormeans to position any opening of any disk in line with the light ray.

2. In a traific indicator, a screen, means for projecting light rays ina spot upon the screen, a plurality of discs overlapping the light raysat one edge, each disc having a plurality of transparent openings andsome with opaque designations therein, movable to position any openingin the path 'of the light rays, and stop motor means operable tomoveeach disc independently to position an selected opening in the pathof the light ray, the designation in the opening being reproduced in thelight spot upon the screen.

3. In an airway traflic indicator, a screen, means for projecting lightrays in a spot upon the screen, a plurality of opaque discs to interceptthe light rays eachhaving openings therein one with transparent colorsand another with opaque designations therein which appear in the lightspot on the screen when the light rays are directed through the openingsof both discs, different colors denoting different altitudes anddifferent designations denoting different air ships or flights, and aseparate motor means for moving each disc to position any one of thedifferent openings in the path of the light rays, and the ill Ill

color and other designations appearing on the same spot on the screen.

4. In a traflic indicator for ships and air ships, a screen having a mapand landmark indications, means for projecting light rays in a spot uponthe screen, a plurality of opaque discs to intercept the light rays eachhaving openings therein one with different colors and another withopaque designations therein which appear in the light spot on the screenwhen the light rays are directed through the openings, different colorsdenoting different altitudes for airships and other designationsdenoting different airships or flights, a separate motor for moving eachdisc to position any selected one of the difierent openings into thepath of the light rays, and means comprising a pair of mirrors and meansto move them jointly and separately to deflect the rays and tocontinuously change them in moving the spot on the screen to indicatethe direction and speed of movement of the airship.

5. In a directional airway tramc indicator, a screen having a mapthereon, means for projecting rays of light to form a spot on thescreen, a pair of movable mirrors for moving the spot directionally uponthe screen, an electric motor for each mirror. either mirror movable atan angle to the other, a two phase current supply with one motor fieldin one phase and the other motor field in the other phase, anddirectional means for operating the motors comprising induction coils inquadrature with relation to each other and connected to the motorfields, and a rotatable induction coil movable relatively to the saidinduction coils to actuate either one or both of the motors accordinglyand thereby to move the mirrors jointly and separately and the spot oflight in the resultant directional path on the screen.

6. In a directional airway traflic indicator, a screen having a mapthereon, means for projecting rays of light to form a spot on thescreen, a

pair of movable mirrors for moving the spot directionally upon thescreen, an electric motor for each mirror, either mirror movable at anangle to the other, a two phase current supply with one motor field inone phase and the other motor field in the other phase, and directionalmeans for operating the motors comprising induction coils in quadraturewith relation to each other and connected to the motor fields, arotatable induction coil movable relatively to the said induction coilsto actuate either one or both of the motors accordingly and thereby tomove the mirrors and the spot of light in a resultant directional pathon the screen, and speed changing means for the motors comprising motorcurrent coils in series and connected to the rotatable induction coilthrough a variable resistance, the variation of the resistance changingthe speeds of the motors and the corresponding movements of the mirrorschanging the speed of movement of the spot of light in the resultantdirectional path on th screen.

'7. In a directional airway trafilc indicator, a screen having a mapthereon, means for projecting rays of light to form a spot on thescreen, a pair of movable mirrors for moving the spot directionally uponthe screen, an electric motor for each mirror, either mirrormovable atan angle to the other, a two phase current supply with one motor fieldin one phase and the other motor field in the other phase, anddirectional means for operating the motors comprising two sets ofinduction coils in quadrature and connected to the 7 motor fields, aninduction coil movable relatively to the coils of one set of inductioncoils to modify the fields of either one or both of the motors accordingto the reported direction of movement of a ship and another inductioncoil movable relatively to another setof induction coils to modify thefields of either one or both of the motors according to the reporteddirection of the wind,

the motors operating the mirrors accordingly and moving the spot oflight on the screen in a path which is a resultant of the ships reporteddirection and the direction of the wind.

8. In a directional airway traffic indicator, a screen having a mapthereon, means for projecting rays of light to form a spot on thescreen, a pair of movable mirrors for moving the spot directionally uponthe screen, an electric motor for each mirror, either mirror movable atan angle to the other, a two phase current supply with one motor fieldin one phase and the other motor field in the other phase, anddirectional means for operating the motors comprising two sets ofinduction coils in quadrature and connected to the motor fields, aninduction coil movable relatively to the coils of one set of inductioncoils to modify the fields of either one or both of the motors accordingto the reported direction of movement of a ship, another induction coilmovable relatively to another set of induction coils to modify thefields of either one or both of the motors according to the reporteddirection of the wind, the motors operating the mirrors accordingly andmoving the spot of light on the screen in a path which is a resultant ofthe ship's reported direction and the direction of the wind, and speedchanging means for the motors comprising motor current coils in seriesand connected to each of the movable induction coils through a variableresistance, the variation of the resistances changing the speeds of themotors and the resultant speeds of the motors depending upon thereported speeds of the ship and the wind, the motors operating themirrors in accordance with the variations of the movable induction coilsand the resistances to move the spot of light on the screen which is aresultant of the-reported speed and direction of the ship and of thewind.

9. In a traflic indicator of the class described, a screen having a mapthereon, means for projecting light rays in a spot on the screen, a pairof movable mirrors for deflecting the rays and directionally moving thespot on the map of the screen; means for driving each mirror comprisinga motor, a gear segment connected to the mirror, and a drivingconnection between the motor and the gear segment including a slipclutch; and means to actuate each gear segment independently of themotor movement for moving each mirror to reset the spot at a differentlocation.

10. In a traflic indicator of the class described, a screen having a mapthereon, means for projecting light rays in a spot on the screen, a pairof movable mirrors for deflecting the rays and directionally moving thespot on the map of the screen; means for driving each mirror comprisinga motor, a gear segment connected to the mirror, and a drivingconnection between the motor and the gear segment including a slipclutch; and means to set the spot at a predetermined location on the mapby moving either one or both of the mirrors and each comprising amanuallyoperable knob and a connection from the knob to the gearsegment, the slip clutch operating to protect, the motor drive to thegear segment.

11. In a traffic indicator of the class described, a screen having a mapthereon, means for projecting light rays in a spot on thescreen, a pairof movable mirrors for deflecting the rays and directionally moving thespot on the map of the screen; means for driving each mirror comprisinga motor, a gear segment connected to the mirror, a pinion engaging thegear segment, a driving shaft for the pinion, a slip clutch normallyconnecting the motor and the driving shaft; and means to independentlyset each mirror comprising a manually operable knob, and a connectionbetween the knob and the driving shaft for the pinion to operate thegear segment separately from the motor movement because of the slipclutch, the spot on the screen being moved and set accordingly.

12. In a traffic indicator of the class described, a'screen having a mapthereon, means for projecting light rays in a spot on the screen, meansto modify the light rays and impart different colors to the spot toindicate different flight altitudes, means to modify the light rays andapply different numerals to the light spot to indicate different ships,a pair of movable mirrors for deflecting the rays and directionallymoving the spot on the map of the screen, means for moving each mirrorccmprising a gear segment connected thereto, a pinion engaging thesegment, a shaft to which the pinion is connected, a driving motor foreach mirror, a slip clutch normally connecting each motor with itscorresponding shaft, and means for independently setting each mirror andadjusting the spot accordingly com prising a manually operable knob, anda driving connection between the knob and the shaft for separatelyrotating the pinion and the gear segment for the mirror free from themotor movement because of the slip clutch.

13. In a traffic indicator for ships and air ships, means for projectinglight rays, 3. screen having a map and landmark indications, and meansto receive and direct the light rays upon the screen comprising a pairof mirrors movable at different angles with respect to each other, andmotor means connected with the mirrors for jointly and separately movingthem to deflect the light rays in a spot on the screen and to changethem continuously for moving the spot in any desired direction toindicate the direction and speed of movement of the ship.

EARL W. SPRINGER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,985,265 Smith Dec. 25, 19342,433,860 McDowell Jan. 6, 1948 FOREIGN PATENTS Number Country Date460,997 Great Britain Feb. 8, 1937 473,024 Great Britain Oct. 4, 1937

